Nothing special happens at 15 years expenses in savings. It's way past what you need for security, but not nearly enough to retire on (that's more like 25x). It's way past what you need to rent, but it won't buy you a home you want in the region where you earned it, unless in combination with a PITI that commits you to earning at the same level for another 30 years. It could set you up nicely in a different region, but that would probably have to be combined with a career change, or else you're gambling that you can sustain full-remote employment.

If you're telling yourself to hang on until you reach this point... just realize that you may reach it and find you're still stuck.